Extruded polystyrene foam vs. polystyrene foam: what's the difference?

What is extruded polystyrene?

Extruded polystyrene is a plastic used to make a variety of products from construction materials to storage containers. The product may also be called XPS, after the popular branded version of this material also known as Styrofoam. depending on the application, extruded polystyrene can take the form of a dense foam, or a stronger plastic-like material.

Manufacturers make polystyrene from hydrocarbon molecules, which are a byproduct of the petroleum refining process. The polystyrene pellets are then melted at high temperatures and injected with air. The mixture is placed in a mold, where it is allowed to cool and harden. It may also undergo a more traditional extrusion process, in which it is pressed through a die to form the desired shape. This manufacturing process gives polystyrene a uniform bubble structure and a consistent texture throughout the material.

Extruded polystyrene is used to make many different products, including household and industrial items. It can be molded into shipping containers for electronics or chopped to form foam packing peanuts for shipping and mailing. The material is also used to make food take-out containers as well as disposable cups and plates. Egg cartons, meat trays and other food storage products are also made from this material, as are insulation and other construction materials. Manufacturers can even use extruded polystyrene to make molds for metal and other materials.

Extruded polystyrene foam vs. polystyrene foam

Many things that people think are made of polystyrene foam are actually made of polystyrene. Polystyrene foam is a trademarked brand of closed-cell extruded polystyrene foam or XPS. This foam is also known as "blue board" and is used for building insulation, thermal insulation and waterproofing.

So, what is polystyrene foam made of? Polystyrene foam is made from styrene, which is a petroleum-based product. How is polystyrene foam made? Styrene is refined into polystyrene by polymerization, and then a hydrofluorocarbon reagent is added. This combination is then extruded and expanded under pressure until a foam sheet is formed.

So, if it's not polystyrene foam, what is it?

The foam you used to call foam polystyrene is actually expanded polystyrene foam or EPS. This material is made from polystyrene, a plastic commonly used to make clear products such as food packaging or laboratory equipment. When polystyrene is combined with colorants, additives, or other plastics, it can be used to make toys, car parts, appliances, and more.

EPS is composed primarily of air - about 95 percent, in fact. Over the years, EPS has become the preferred choice for making insulated products such as coffee mugs and coolers. And because it is light, it is used in products that float like rafts and life jackets, and it is often used to transport cushioned products.

While it's true that EPS is not biodegradable, that doesn't mean it can't be recycled. eps foam packaging can be re-extruded into solid polystyrene pellets. These pellets can then be used to make items such as coat hangers, photo frames, food service packaging and more.